The worst thing I ever did was sell my bitcoin at a very cheap price, I had a huge loss. At that time I experienced a sell panic because the price of bitcoin decreased drastically. Yet a few hours later the bitcoin price went up and I thought I made a big mistake, if only I had patience then I could gain the opportunity to keep my bitcoin assets and then sell them at a much higher price. My mental and emotional level is an important part of taking every decision.
I have the same experience like you and I remember that I sold my bitcoin when the price is at $1000 because I am in an urgent situations. I don't think twice in that time and only sell by instant but now, I will hold my bitcoin and I will sell it if the price is more than $20k but if I have an urgent or I need the money then I will sell it to fills my needs. I think I can handle my emotional to not selling my bitcoin even if the price is drop like yesterday and I am happy that I can buy more bitcoin with a low price.